TECHNICAL FIELD
[0001] The present disclosure relates to pack flow through a wireless controller and more
specifically to a layer 2 fast re-switching approach which provides a process of transitioning
from an active wireless controller to a standby wireless controller when the active
wireless controller fails.
BACKGROUND
[0002] FIG. 1 illustrates the general wireless packet flow infrastructure 100 between wireless
devices 102, 104 and the Internet 116. Clients 102,104 connect to an Access Point
(AP) 106 wherein data will be transmitted through an IP CAPWAP (Wireless Access Points
protocol) tunnel 108 to a wireless controller (WLC) 110. Packets will then be natively
layer 2 (L2) forwarded 112, 113 to/from Internet gateway (GW) router 114 for connecting
to the Internet 116.
[0003] A WLC 110 can handle hundreds of thousands of wireless clients 102/104. The WLC 110
needs to be highly redundant with high availability. When the active WLC 110 goes
down, a standby WLC 118 takes over. The wireless clients 102/104 and the AP 106 states
are synced over from the active WLC 110 to the standby WLC 118. The AP 106 also needs
to switch to the new active WLC 118 with a new CAPWAP tunnel end-point 120. After
the WLC fail-over, the clients 102/104 to/from the WLC portion of the traffic is handled
in a fast convergence fashion such that within one second, for example, the traffic
from the clients 102/104 is communicated from the AP 106 through the new tunnel 120
to the new WLC 118. The AP 106 can represent multiple devices and even hundreds to
thousands of devices.
[0004] However, there are additional challenged in the failover process. The portion of
the network between the WLC 110 and the GW 114 is a L2 switch or switch domain 112,
113. For traffic from the GW 114 to the WLC 110, the MAC (Media Access Control) learning
had the path from the GW 114 to the former active WLC device 110. The L2 switch network
112 will not know that the new active WLC 118 has taken over all the client MAC addresses.
The challenge in the fail-over scenario is that it takes real traffic for each of
the MAC addresses of the clients 102/104 to be relearned in order for GW 114 to reach
the new active WLC device 118.
[0005] One way to handle relearning all of the MAC addresses after a fail-over to the new
active WLC 118. The new active WLC 118 will send out gratuitous ARP (Address Resolution
Protocol) signals for each of the clients 102/104 to advertise that the new WLC 118
now owns those MAC addresses. But to handle hundreds of thousands of wireless client
MAC devices, at the moment right after switchover and the device is very busy, would
take a while for all MAC addresses to be finally relearned in the L2 domain 113.
[0006] Thus, even if the system implements an efficient and speedy synchronization of the
clients' information from the active WLC 110 to the standby WLC 118, if the system
does not implement a scalable solution to deal with the re-convergence of hundreds
of thousands of wireless clients on the L2 domain, there remains a need within the
art for a faster convergence approach.
[0007] US 2014/0269535 A1 relates to a method which includes identifying an access point joining a wireless
controller in communication with a switch, establishing a control tunnel between the
access point and the wireless controller, transmitting an address of the switch from
the wireless controller to the access point, and requesting the switch to setup a
data tunnel with the access point.
[0008] US 2011/274036 A1 discloses techniques to support roaming of wireless devices in a network such that
the wireless devices can keep their Internet Protocol (IP) addresses as they roam
within and across mobility sub-domains. When a wireless device roams from one access
switch to another access switch, a tunnelling endpoint apparatus in the wireless device's
home mobility sub-domain is configured to serve as the point of presence for the roamed
wireless device. Traffic for the roamed wireless device is tunneled from the access
switch where the wireless device has roamed (where it is currently attached) to the
tunneling endpoint apparatus. When the wireless device roams across mobility sub-domains,
then traffic is tunneled from the access switch where the wireless device is currently
attached to the tunneling endpoint apparatus in that mobility sub-domain (called a
"foreign" mobility sub-domain) to the tunneling endpoint apparatus in the wireless
device's home mobility sub-domain.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In order to describe the manner in which the above-recited and other advantages and
features of the disclosure can be obtained, a more particular description of the principles
briefly described above will be rendered by reference to specific embodiments thereof
which are illustrated in the appended drawings.
Understanding that these drawings depict only exemplary embodiments of the disclosure
and are not therefore to be considered to be limiting of its scope, the principles
herein are described and explained with additional specificity and detail through
the use of the accompanying drawings in which:
FIG. 1 illustrates an example wireless packet flow through various devices between
a wireless client and the Internet;
FIG. 2 illustrates an example system configuration;
FIG. 3A illustrates a first aspect of the fast re-switch approach;
FIG. 3B illustrates another aspect of the fast re-switch approach;
FIG. 3C illustrates yet another aspect of the fast re-switch approach;
FIG. 4 illustrates a method embodiment;
FIG. 5 illustrates a method embodiment from a switch standpoint; and
FIG. 6 illustrates a method embodiment from a wireless controller standpoint.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0010] The invention is set out in the independent claims and preferred features are set
out in the dependent claims.
[0011] Various embodiments of the disclosure are discussed in detail below. While specific
implementations are discussed, it should be understood that this is done for illustration
purposes only.
Overview
[0012] Additional features and advantages of the disclosure will be set forth in the description
which follows, and in part will be obvious from the description, or can be learned
by practice of the herein disclosed principles. The features and advantages of the
disclosure can be realized and obtained by means of the instruments and combinations
particularly pointed out in the appended claims. These and other features of the disclosure
will become more fully apparent from the following description and appended claims,
or can be learned by the practice of the principles set forth herein.
[0013] Disclosed is a method that enables a transition from a primary active wireless controller
to a standby wireless controller. The method includes establishing a fast re-switch
tunnel between a L2 switch and the standby wireless controller. Once the tunnel is
established, the system can switch from the active wireless controller to the standby
wireless controller and data can be routed from the Internet through the layer to
switching network to the standby wireless controller through the fast re-switch tunnel
prior to updating MAC tables for wireless clients. The method from the standpoint
of the L2 switch includes receiving, at the L2 switch, a first message to establish
a fast re-switch tunnel between the L2 switch and a wireless controller and receiving,
at the L2 switch, a second message to trigger use of the fast re-switch tunnel. The
switch receives data and forwards the data to the standby wireless controller through
the fast re-switch tunnel.
[0014] The standby wireless controller, once it becomes active, can transmit a gratuitous
address resolution protocol request to the wireless clients such that all of the MAC
entries for wireless clients in a table can be updated. Once all the MAC entries are
updated, the fast re-switch tunnel can be removed. Embodiments of the concepts disclosed
herein can be directed to different nodes within the environment. For example, aspects
of the disclosure can be addressed from the standpoint of an L2 switch in layer 2,
which can include any switch and including the switch closest to the active wireless
controller. The disclosure can be addressed from the standpoint of the active wireless
controller or the standby wireless controller. Furthermore, the disclosure can be
directed from the standpoint of a gateway node, an access point, a wireless client,
or any other component which is involved in the management of the pathways associated
with data flow through the layer 2 network.
Detailed Description
[0015] The present disclosure addresses the issues raised above. The disclosure provides
a system, method and computer-readable storage device embodiments. First a general
example system shall be disclosed in FIG. 2 which can provide some basic hardware
components making up a server, node or other computer system.
[0016] First a general example system shall be disclosed in FIG. 2, which can provide some
basic hardware components making up a server, node or other computer system. FIG.
2 illustrates a computing system architecture 200 wherein the components of the system
are in electrical communication with each other using a connector 205. Exemplary system
200 includes a processing unit (CPU or processor) 210 and a system connector 205 that
couples various system components including the system memory 215, such as read only
memory (ROM) 220 and random access memory (RAM) 225, to the processor 210. The system
200 can include a cache of high-speed memory connected directly with, in close proximity
to, or integrated as part of the processor 210. The system 200 can copy data from
the memory 215 and/or the storage device 230 to the cache 212 for quick access by
the processor 210. In this way, the cache can provide a performance boost that avoids
processor 210 delays while waiting for data. These and other modules/services can
control or be configured to control the processor 210 to perform various actions.
Other system memory 215 may be available for use as well. The memory 215 can include
multiple different types of memory with different performance characteristics. The
processor 210 can include any general purpose processor and a hardware module or software
module/service, such as service 1 232, service 2 234, and service 3 236 stored in
storage device 230, configured to control the processor 210 as well as a special-purpose
processor where software instructions are incorporated into the actual processor design.
The processor 210 may essentially be a completely self-contained computing system,
containing multiple cores or processors, a bus (connector), memory controller, cache,
etc. A multi-core processor may be symmetric or asymmetric.
[0017] To enable user interaction with the computing device 200, an input device 245 can
represent any number of input mechanisms, such as a microphone for speech, a touch-sensitive
screen for gesture or graphical input, keyboard, mouse, motion input, speech and so
forth. An output device 235 can also be one or more of a number of output mechanisms
known to those of skill in the art. In some instances, multimodal systems can enable
a user to provide multiple types of input to communicate with the computing device
200. The communications interface 240 can generally govern and manage the user input
and system output. There is no restriction on operating on any particular hardware
arrangement and therefore the basic features here may easily be substituted for improved
hardware or firmware arrangements as they are developed.
[0018] Storage device 230 is a non-volatile memory and can be a hard disk or other types
of computer readable media which can store data that are accessible by a computer,
such as magnetic cassettes, flash memory cards, solid state memory devices, digital
versatile disks, cartridges, random access memories (RAMs) 225, read only memory (ROM)
220, and hybrids thereof.
[0019] The storage device 230 can include software services 232, 234, 236 for controlling
the processor 210. Other hardware or software modules/services are contemplated. The
storage device 230 can be connected to the system connector 205. In one aspect, a
hardware module that performs a particular function can include the software component
stored in a computer-readable medium in connection with the necessary hardware components,
such as the processor 210, connector 205, display 235, and so forth, to carry out
the function.
[0020] According to an aspect of this disclosure, the Active/Standby WLC interface 110 is
with the Internet Gateway (GW) 114 in the layer 2 (L2) domain 112. This part is not
an IP/IPv6 network. The GW 114 treats the WLC 110 as part of the switch domain. The
virtual router redundancy protocol, which provides for automatic assignment of available
Internet Protocol routers for participating hosts, does not apply in this case. The
L2 domain switches 112 in this disclosure relate to the OSI L2 switch routing functionality.
The basic idea is to use controller intelligence design routes through an Ethernet
switched network that avoid the use of broadcast when the route to the destination
is known. L2 is the data link layer that provides node-to-node data transfer. It is
a link between two directly connected nodes, which, in this case, is the Gateway 114
and the WLC 110 or WLC 118. The data link L2, in one application, is divided into
two sub layers, including the MAC layer which is responsible for controlling how devices
in a network gain access to a medium and permission to transmit data and a logical
link control layer, which is responsible for identifying and encapsulating network
layer protocols, and controls error checking and frame synchronization.
[0021] FIGs. 3A, 3B and 3C illustrate an example network architecture 300 according to an
aspect of this disclosure. FIG. 4 illustrates a method embodiment. These figures will
be discussed together with the following example.
[0022] In FIG. 3A, the traffic 304 from the Internet to the wireless clients 102/104 stops
at the L2 switch 'S 1' 302 after a failure of the WLC 110. If this traffic can be
re-switched towards the new active WLC 118, then the blackholing before the re-convergence
of the L2 network can be minimized.
[0023] As shown in FIG. 3B, before a switch-over from an active WLC 110 the new WLC 118,
the active WLC 110 sends a signal/message to a switch 'S 1' 302 (402). The switch
302 can be directly connected to the WLC 110, or may be any other switch in layer
2 that can be configured with this functionality. The path 304 prior to switchover
as is shown in FIG. 3A from the Internet 116, through the GW 114, through L2 Switch
S3 310, through L2 Switch S1 302 to the WLC 110. Switch S1 has a MAC table with all
of the entries for all the clients 102/104 of the APs 106. The message instructs the
switch S1 302 to setup a backup path to MAC address 'M2' (the MAC address of the new
WLC 118) for all the traffic that comes to the WLC 110. The MAC address 'M2' is the
MAC address of the standby WLC interface 118 connecting to the L2 switch domain 112.
The active WLC 110 can learn the M2 MAC address for the standby the WLC 118 from the
standby the WLC 118 since the active WLC 110 and the standby the WLC 118 synchronize
the wireless client 102/104 and AP 106 states. The active WLC 110 also instructs the
standby WLC 118 that the fast re-switch point of local repair (PLR) is 'S1' 302 (with
MAC address 'M3', for example) (404).
[0024] The signal or message can be a L2 packet, for example use the CMP (Cisco MetaData
Protocol) in the similar way as a security group tag (SGT) tag is defined. The switch
'S1' 302 is the only L2 device that needs to support the functionality disclosed herein.
When 'S1' 302 receives the signal/message from the WLC 110, the switch S1 302 sets
up the forwarding chain such that the normal traffic for all the WLC 110 related MAC
addresses will go to the port towards the current active WLC 110, and the standby
forwarding will have a MAC over MAC tunnel to reach the destination MAC of 'M2' (at
the new WLC 118) for the fast re-switch later. In FIG. 3B, the data on pathway 322
from the Internet 116, through the GW 114, and L2 switch S3 310 flows to L2 Switch
S1 and then is tunneled 326 (as triggered by the steps outline in the next paragraph)
through L2 Switch S3 and L2 Switch S2 to the new WLC 118. This process basically involves
pre-setting up a tunnel to the M2 address such that if the link goes down to WLC 110,
the L2 Switch S1 302 can send the traffic that used to be sent to WLC 110 over to
WLC 118 at MAC address M2. Any communications, handshakes, confirmations, and so forth
can be established during this stage to acknowledge that WLC 118 is willing to accept
traffic originally intended for WLC 110.
[0025] Next the process includes switching over from the WLC 110 to the stand-by WLC 118
(406). The new active WLC 118 knows that it is now the master and will send a L2 signal/message
324 to switch 'S1' 302 (using MAC 'M3', for example) which instructs the switch S1
302 to trigger the fast re-switch setup such that traffic flows 326 to 'M2' now (408).
The pre-setup was established above, and this step involves activating or triggering
the fast re-switch setup which causes the traffic to utilize the new path to the WLC
118. There can be any amount of time before the pre-setup and the actual triggering.
Furthermore, the timing of the instruction to pre-set up the tunnel and the triggering
can be determined based on a number of factors. For example, WLC 110 may predict that
within one hour, there is a likelihood that it will fail. WLC 110 can, based on the
prediction of the timing of when a failure is likely, or based on any other factor,
can transmit the signal to S1 302 to initiate the pre-set up. Other factors outside
of the WLC 110 can be communicated to the WLC 110 such that it sends the instruction.
The instruction can also come from another source and not the WLC 110. Another node
in the network, and administrator, a network-based service, and so forth, could cause
the instruction to be sent to S1 302 to initiate the preset up process.
[0026] The 'S1' 302, based on the message from the new WLC 118, flips the forwarding active/standby
path decision on the forwarding chain 326. The result of this operation is that all
the traffic that was to be sent to the port for the previous WLC 110 is now encapsulated
with another MAC tunnel 326 with destination address of MAC 'M2' 118. Since the new
active WLC 118 sends a L2 signal 324 to S1' 302 for triggering, the MAC 'M2' is learned
throughout the L2 domain from the new active WLC 118 to 'S1' 302.
[0027] All the traffic from the Internet 116 to respective wireless clients 102/104, if
the traffic reaches the switch 'S1', will be fast re-switched 326 to the new active
WLC 118. It will be further sent to the AP 106 and clients 102/104 by the WLC 118
via path 328.
[0028] In the meantime, the new active WLC 118 can send out gratuitous address resolution
protocol (GARP) signals for all of its wireless clients 102/104 (410). This is shown
in FIG. 3C. This process may take 10 minutes to complete, but it is needed to have
traffic eventually go through the optimal path 342 in the L2 network. Note that after
the GARP, that L2 Switch S1302 is bypassed in the path of traffic to the new WLC 118.
After all the MAC addresses are processed with the GARP, the new active WLC 118 can
send another signal/message to 'S1' (MAC 'M3' for example) to have it tear down the
fast re-switch setup and to remove this state from the switch (412). This signal to
tear down the tunnel that was created by S1 302 can also come from any other node
in the network.
[0029] The L2 fast re-switch approach works in a general L2 switch network and does not
depend on the network topology. Even when the 'S1' and 'S2' switches represent a single
combined switch, the mechanism works the same without change.
[0030] A more secure and reliable mechanism can add a 'keepalive' message (once every 5
minutes for example) between the 'S1' Switch 302 and the standby WLC 118 after step
(402) above. This is to make sure the standby WLC 118 will accept the tunneled-over
traffic after switch-over, and also to make sure the path between them is not broken
before the switch-over happens.
[0031] Multicast traffic from the Internet 116 to the clients 102/104 will be handled the
same way during the fast re-switch. Normally after switch-over to the new active WLC
118, multicast traffic needs to wait until the client sending out the periodical Internet
group management protocol (IGMP) reports which is once a minute by default. With this
L2 fast re-switching, the multicast packets received on 'S1' 302 will be MAC encapsulated
to the new active WLC 118 to reach the wireless clients 102/104. The L2 fast re-switch
can be applied to some use cases other than the WLC high availability. The mechanism
can be standardized for multiple vendor support.
[0032] The fast re-switching approach disclosed herein is the industry's first L2 fast re-switch
for the application of wireless controller high availability. It uses a MAC over MAC
tunnel to achieve the fast convergence in a scalable way after the WLC switchover
in the L2 switch domain between the WLC 110/118 and Internet gateway router 114.
[0033] The L2 solution is simple and effective, and can scale to a very large number of
clients of a wireless controller with the same fast convergence time. Only one external
device to the WLC 110 needs to support this mechanism and rest of the L2 domain does
not need to understand this feature. In the example above, a directly connected L2
switch 302 is the supporting device, but other layer 2 switches or any other node
could be used as well. It does not have the problem of long delay by only sending
out gratuitous ARP for relearning of MAC addresses in L2 domain. The approach is not
restricted to switches and topology as in using the Virtual Switching System (VSS)
switches with dual active/standby links. The approach also does not need to run a
border gateway protocol (BGP) Ethernet virtual private network/ locator identify separation
protocol (EVPN/LISP) complex overlay protocol mechanism. Further, the approach does
not need to flushout the MAC addresses as in overlay transport virtualization (OTV)
case then to relearn every one of them.
[0034] This disclosure realizes that the L2 switch domain cannot relearn a large of the
MAC addresses very fast (e.g. < 1 sec) and the system needs to use the concept of
IP network's fast reroute (FRR) which is independent of number of route entries. The
concept disclosed herein is an L2 fast re-switch approach which takes certain steps
to more efficiently manage a switch over from one WLC 110 to another WLC 118.
[0035] Embodiments of the concepts disclosed herein can be claim from the standpoint of
different nodes within the environment. For example, aspects of the disclosure can
be addressed from the standpoint of an L2 switch in layer 2, which can include any
switch and includes the L2 switch 302 as the closest switch to the active wireless
controller 110. The disclosure can be addressed from the standpoint of the active
wireless controller 110 or the standby wireless controller 118. Furthermore, the disclosure
can be directed from the standpoint of a gateway node 114, an access point 106, a
wireless client 102/104, or any other component which is involved in the management
of the pathways associated with dataflow through the layer 2 network.
[0036] FIG. 5 illustrates an aspect of this disclosure from the standpoint of an L2 switch.
The L2 switch 302 is preferably, the L2 switch that is nearest physically or virtually
to the active WLC 110, although it could also be any switch in the layer. The method
includes receiving, at a L2 switch, a first message to establish a fast re-switch
tunnel between the L2 switch and a wireless controller (502), receiving, at the L2
switch, a second message to trigger use of the fast re-switch tunnel (504), receiving
data at the L2 switch (506) and forwarding the data to the wireless controller through
the fast re-switch tunnel (508).
[0037] The L2 switch can receive the first message from a first wireless controller or from
any other node within the network. The wireless controller can be a second wireless
controller that is different from the first wireless controller. In one example, the
second wireless controller is the standby or backup wireless controller 118 and the
first wireless controller can be the active wireless controller 110. The method further
includes receiving, at the L2 switch, a MAC address of the wireless controller. This
of course enables the set up of the fast re-switch tunnel 326, which can occur prior
to a switchover to the standby WLC 118.
[0038] The method can also include receiving, at the L2 switch 302, a third message instructing
the L2 switch 302 to tear down the fast re-switch tunnel 326. This message can be
received after a completion of a gratuitous address resolution protocol transmission
process associated with the wireless controller. The GARP process involves the slower
process of updating MAC tables for all of the wireless clients 102/104 being served
by the standby WLC 118.
[0039] FIG. 6 illustrates an embodiment from the standpoint of the standby wireless controller
118. The method includes receiving, at a stand-by wireless controller and from an
active wireless controller, a MAC address of a L2 switch
[0040] (602), transmitting, after the L2 switch establishes a fast re-switch tunnel between
the L2 switch and the stand-by wireless controller, after controller fail-over and
after the stand-by controller becomes the active controller (or one or more of these
events), a message to the L2 switch to activate the fast re-switch tunnel (604) and
receiving data initially intended for the active wireless controller at the stand-by
wireless controller via the fast re-switch tunnel (606). The method can further include
transmitting a gratuitous address resolution protocol notice to clients of the stand-by
wireless controller. After a completion of a process of filling a MAC table with entries
for the clients based on transmitting the gratuitous address resolution protocol notice,
the method can include transmitting a second message to the L2 switch to tear down
the fast re-switch tunnel. Another aspect can include receiving additional data at
the stand-by wireless controller after the fast re-switch tunnel is torn down.
[0041] In summary, disclosed is a method that includes receiving, at a layer 2 switch, a
first message to establish a fast re-switch tunnel between the layer 2 switch and
a standby wireless controller and receiving, at the layer 2 switch, a second message
to trigger use of the fast re-switch tunnel. The switch receives data and forwards
the data to the standby wireless controller through the fast re-switch tunnel. Once
MAC tables are updated for the standby wireless controller, the fast re-switch tunnel
can be torn down.
[0042] In some embodiments the computer-readable storage devices, mediums, and/or memories
can include a cable or wireless signal containing a bit stream and the like. However,
when mentioned, non-transitory computer-readable storage media expressly exclude media
such as energy, carrier signals, electromagnetic waves, and signals per se.
[0043] Methods according to the above-described examples can be implemented using computer-executable
instructions that are stored or otherwise available from computer readable media.
Such instructions can include, for example, instructions and data which cause or otherwise
configure a general purpose computer, special purpose computer, or special purpose
processing device to perform a certain function or group of functions. Portions of
computer resources used can be accessible over a network. The computer executable
instructions may be, for example, binaries, intermediate format instructions such
as assembly language, firmware, or source code. Examples of computer-readable media
that may be used to store instructions, information used, and/or information created
during methods according to described examples include magnetic or optical disks,
flash memory, USB devices provided with non-volatile memory, networked storage devices,
and so on.
[0044] Devices implementing methods according to these disclosures can include hardware,
firmware and/or software, and can take any of a variety of form factors. Typical examples
of such form factors include laptops, smart phones, small form factor personal computers,
personal digital assistants, rackmount devices, standalone devices, and so on. Functionality
described herein also can be embodied in peripherals or add-in cards. Such functionality
can also be implemented on a circuit board among different chips or different processes
executing in a single device, by way of further example.
[0045] The instructions, media for conveying such instructions, computing resources for
executing them, and other structures for supporting such computing resources are means
for providing the functions described in these disclosures.
[0046] Although a variety of examples and other information was used to explain aspects
within the scope of the appended claims, no limitation of the claims should be implied
based on particular features or arrangements in such examples, as one of ordinary
skill would be able to use these examples to derive a wide variety of implementations.
Further and although some subject matter may have been described in language specific
to examples of structural features and/or method steps, it is to be understood that
the subject matter defined in the appended claims is not necessarily limited to these
described features or acts. For example, such functionality can be distributed differently
or performed in components other than those identified herein. Rather, the described
features and steps are disclosed as examples of components of systems and methods
within the scope of the appended claims. Moreover, claim language reciting "at least
one of" a set indicates that one member of the set or multiple members of the set
satisfy the claim.
[0047] Moreover, claim language reciting "at least one of" a set indicates that one member
of the set or multiple members of the set satisfy the claim. For example,
claim language reciting "at least one of A, B, and C" or "at least one of A, B, or
C" means A alone, B alone, C alone, A and B together, A and C together, B and C together,
or A, B and C together.
1. A method for transitioning from an active wireless controller to a standby wireless
controller, comprising:
receiving (502), at a layer 2 switch (302), a first message to establish a fast re-switch
tunnel for switching from a first wireless controller (110) to a second wireless controller
(118), wherein the fast re-switch tunnel is between the layer 2 switch (302) and the
second wireless controller (118), wherein the first wireless controller (110) is an
active wireless controller, and wherein the second wireless controller (118) is a
standby wireless controller;
in response to receiving the first message, setting up, by the layer 2 switch (302),
the fast re-switch tunnel as a standby backup path to the second wireless controller
(118) for data intended for the first wireless controller (110);
receiving (504), at the layer 2 switch (302), a second message (324) to trigger use
of the fast re-switch tunnel;
in response to receiving the second message, activating the fast re-switch tunnel;
receiving (506) data at the layer 2 switch (302) intended for the first wireless controller
(110); and
forwarding (508) the data to the second wireless controller (118) through the fast
re-switch tunnel instead of to the first wireless controller (110) to transition from
the active wireless controller to the standby wireless controller.
2. The method of claim 1, wherein the layer 2 switch (302) receives the first message
from the first wireless controller (110).
3. The method of any of claims 1 to 2, further comprising:
receiving, at the layer 2 switch (302), a MAC address of the second wireless controller
(118).
4. The method of any of claims 1 to 3, further comprising:
receiving, at the layer 2 switch (302), a third message instructing the layer 2 switch
(302) to tear down the fast re-switch tunnel, optionally wherein receiving the third
message occurs after a completion of a gratuitous address resolution protocol transmission
process associated with the second wireless controller (118).
5. A method comprising:
receiving (602), at a stand-by wireless controller (118) and from an active wireless
controller (110), a MAC address of a layer 2 switch (302);
transmitting (604), after the layer 2 switch (302) establishes a fast re-switch tunnel
between the layer 2 switch (302) and the stand-by wireless controller (118), a message
(324) to the layer 2 switch (302) to activate the fast re-switch tunnel; and
receiving (606) data initially intended for the active wireless controller (110) at
the standby wireless controller (118) via the fast re-switch tunnel.
6. The method of claim 5, further comprising:
transmitting a gratuitous address resolution protocol notice to clients of the stand-by
wireless controller (118), optionally wherein after a completion of a process of filling
a MAC table with entries for the clients based on transmitting the gratuitous address
resolution protocol notice, transmitting a second message to the layer 2 switch (302)
to tear down the fast re-switch tunnel, optionally further comprising:
receiving additional data at the stand-by wireless controller (118) after the fast
re-switch tunnel is torn down.
7. The method of claim 5 or 6, wherein the transmitting of the message (324) to the layer
2 switch (302) to activate the fast re-switch tunnel occurs after the active wireless
controller (110) ceases working.
8. The method of any of claims 5 to 7, further comprising:
switching data flow from the active wireless controller (110) to the stand-by wireless
controller (118).
9. The method of any of claims 5 to 8, wherein the data is received from a gateway (114)
to the layer 2 switch (302).
10. The method of any of claims 5 to 9, further comprising:
receiving additional data at the stand-by wireless controller (118) after MAC entries
for clients (102, 104) of access points (106) associated with the stand-by wireless
controller (118) are complete and after the fast re-switch tunnel is torn down.
11. Apparatus comprising:
means for receiving (502), at a layer 2 switch (302), a first message to establish
a fast re-switch tunnel for switching from a first wireless controller (110) to a
second wireless controller (118), wherein the fast re-switch tunnel is between the
layer 2 switch (302) and the second wireless controller (118), wherein the first wireless
controller (110) is an active wireless controller, and wherein the second wireless
controller (118) is a standby wireless controller;
means for setting up, by the layer 2 switch (302), in response to receiving the first
message, the fast re-switch tunnel as a standby backup path to the second wireless
controller (118) for data intended for the first wireless controller (110);
means for receiving (504), at the layer 2 switch (302), a second message (324) to
trigger use of the fast re-switch tunnel;
means for activating, in response to receiving the second message, the fast re-switch
tunnel;
means for receiving (506) data at the layer 2 switch (302) intended for the first
wireless controller (110); and
means for forwarding (508) the data to the second wireless controller (118) through
the fast re-switch tunnel instead of to the first wireless controller (110) to transition
from the active wireless controller to the standby wireless controller.
12. The apparatus of claim 11, further comprising means for implementing the method according
to any of claims 2 to 4.
13. Apparatus comprising:
means for receiving (602), at a stand-by wireless controller (118) and from an active
wireless controller (110), a MAC address of a layer 2 switch (302);
means for transmitting (604), after the layer 2 switch (302) establishes a fast re-switch
tunnel between the layer 2 switch (302) and the stand-by wireless controller (118),
a message (324) to the layer 2 switch (302) to activate the fast re-switch tunnel;
and
means for receiving (606) data initially intended for the active wireless controller
(110) at the stand-by wireless controller (118) via the fast re-switch tunnel.
14. The apparatus of claim 13, further comprising means for implementing the method of
any of claims 6 to 10.
15. A computer program, computer program product or computer readable medium comprising
instructions which, when executed by a computer, cause the computer to carry out the
steps of the method of any of claims 1 to 4 or any of claims 5 to 10.
1. Verfahren zum Wechseln von einem aktiven drahtlosen Controller zu einem drahtlosen
Standby-Controller, das Folgendes umfasst:
Empfangen (502), an einer Schicht-2-Schaltung (302), einer ersten Nachricht, um einen
Schnell-Umschalt-Tunnel zum Umschalten von einem ersten drahtlosen Controller (110)
zu einem zweiten drahtlosen Controller (118) aufzubauen, wobei der Schnell-Umschalt-Tunnel
zwischen der Schicht-2-Schaltung (302) und dem zweiten drahtlosen Controller (118)
liegt, wobei der erste drahtlose Controller (110) ein aktiver drahtloser Controller
ist, und wobei der zweite drahtlose Controller (118) ein drahtloser Standby-Controller
ist;
als Reaktion auf den Empfang der ersten Nachricht, Einrichten, durch die Schicht-2-Schaltung
(302), des Schnell-Umschalt-Tunnels als Standby-Backup-Pfad zu dem zweiten drahtlosen
Controller (118) für Daten, die für den ersten drahtlosen Controller (110) bestimmt
sind;
Empfangen (504), an der Schicht-2-Schaltung (302), einer zweiten Nachricht (324),
um die Verwendung des Schnell-Umschalt-Tunnels auszulösen;
als Reaktion auf den Empfang der zweiten Nachricht, Aktivieren des Schnell-Umschalt-Tunnels;
Empfangen (506) von Daten an der Schicht-2-Schaltung (302), die für den ersten drahtlosen
Controller (110) bestimmt sind; und
Weiterleiten (508) der Daten an den zweiten drahtlosen Controller (118) durch den
Schnell-Umschalt-Tunnel anstelle des ersten drahtlosen Controllers (110), um von dem
aktiven drahtlosen Controller zu dem drahtlosen Standby-Controller zu wechseln.
2. Verfahren nach Anspruch 1, wobei die Schicht-2-Schaltung (302) die erste Nachricht
von dem ersten drahtlosen Controller (110) empfängt.
3. Verfahren nach einem der Ansprüche 1 bis 2, das ferner Folgendes umfasst:
Empfangen, an der Schicht-2-Schaltung (302), einer MAC-Adresse des zweiten drahtlosen
Controllers (118).
4. Verfahren nach einem der Ansprüche 1 bis 3, das ferner Folgendes umfasst:
Empfangen, an der Schicht-2-Schaltung (302), einer dritten Nachricht, die die Schicht-2-Schaltung
(302) anweist, den Schnell-Umschalt-Tunnel abzubauen, optional wobei der Empfang der
dritten Nachricht nach einem Abschluss eines dem zweiten drahtlosen Controller (118)
zuzuordnenden unentgeltlichen Adressauflösungsprotokoll-Übertragungsprozesses erfolgt.
5. Verfahren, das Folgendes umfasst:
Empfangen (602), an einem drahtlosen Standby-Controller (118) und von einem aktiven
drahtlosen Controller (110), einer MAC-Adresse einer Schicht-2-Schaltung (302);
Übertragen (604), nachdem die Schicht-2-Schaltung (302) einen Schnell-Umschalt-Tunnel
zwischen der Schicht-2-Schaltung (302) und dem drahtlosen Standby-Controller (118)
aufgebaut hat, einer Nachricht (324) an die Schicht-2-Schaltung (302), um den Schnell-Umschalt-Tunnel
zu aktivieren; und
Empfangen (606) von Daten, die ursprünglich für den aktiven drahtlosen Controller
(110) bestimmt waren, an dem drahtlosen Standby-Controller (118) über den Schnell-Umschalt-Tunnel.
6. Verfahren nach Anspruch 5, das ferner Folgendes umfasst:
Übertragen einer unentgeltlichen Adressauflösungsprotokoll-Nachricht an Clients des
drahtlosen Standby-Controllers (118), optional wobei nach einem Abschluss eines Prozesses
zum Füllen einer MAC-Tabelle mit Einträgen für die Clients basierend auf der Übertragung
der unentgeltlichen Adressauflösungsprotokoll-Nachricht Folgendes ausgeführt wird,
Übertragen einer zweiten Nachricht an die Schicht-2-Schaltung (302), um den Schnell-Umschalt-Tunnel
abzubauen, optional ferner umfassend:
Empfangen zusätzlicher Daten an dem drahtlosen Standby-Controller (118), nachdem der
Schnell-Umschalt-Tunnel abgebaut wurde.
7. Verfahren nach Anspruch 5 oder 6, wobei die Übermittlung der Nachricht (324) an die
Schicht-2-Schaltung (302) zur Aktivierung des Schnell-Umschalt-Tunnels erfolgt, nachdem
der aktive drahtlose Controller (110) seine Arbeit eingestellt hat.
8. Verfahren nach einem der Ansprüche 5 bis 7, das ferner Folgendes umfasst:
Umschalten des Datenflusses von dem aktiven drahtlosen Controller (110) auf den drahtlosen
Standby-Controller (118) .
9. Verfahren nach einem der Ansprüche 5 bis 8, wobei die Daten von einem Gateway (114)
zur Schicht-2-Schaltung (302) empfangen werden.
10. Verfahren nach einem der Ansprüche 5 bis 9, das ferner Folgendes umfasst:
Empfangen zusätzlicher Daten an dem drahtlosen Standby-Controller (118), nachdem MAC-Einträge
für Clients (102, 104) von Zugangspunkten (106), die dem drahtlosen Standby-Controller
(118) zugeordnet sind, abgeschlossen sind und nachdem der Schnell-Umschalt-Tunnel
abgebaut wurde.
11. Vorrichtung, die Folgendes umfasst:
ein Mittel zum Empfangen (502), an einer Schicht-2-Schaltung (302), einer ersten Nachricht,
um einen Schnell-Umschalt-Tunnel zum Umschalten von einem ersten drahtlosen Controller
(110) zu einem zweiten drahtlosen Controller (118) aufzubauen, wobei der Schnell-Umschalt-Tunnel
zwischen der Schicht-2-Schaltung (302) und dem zweiten drahtlosen Controller (118)
liegt, wobei der erste drahtlose Controller (110) ein aktiver drahtloser Controller
ist, und wobei der zweite drahtlose Controller (118) ein drahtloser Standby-Controller
ist;
ein Mittel zum Einrichten, durch die Schicht-2-Schaltung (302), als Reaktion auf den
Empfang der ersten Nachricht, des Schnell-Umschalt-Tunnels als Standby-Backup-Pfad
zu dem zweiten drahtlosen Controller (118) für Daten, die für den ersten drahtlosen
Controller (110) bestimmt sind;
ein Mittel zum Empfangen (504), an der Schicht-2-Schaltung (302), einer zweiten Nachricht
(324), um die Verwendung des Schnell-Umschalt-Tunnels auszulösen;
ein Mittel zum Aktivieren des Schnell-Umschalt-Tunnels als Reaktion auf den Empfang
der zweiten Nachricht;
ein Mittel zum Empfangen (506) von Daten an der Schicht-2-Schaltung (302), die für
den ersten drahtlosen Controller (110) bestimmt sind; und
ein Mittel zum Weiterleiten (508) der Daten an den zweiten drahtlosen Controller (118)
durch den Schnell-Umschalt-Tunnel anstelle des ersten drahtlosen Controllers (110),
um von dem aktiven drahtlosen Controller zu dem drahtlosen Standby-Controller zu wechseln.
12. Vorrichtung nach Anspruch 11, das ferner ein Mittel zum Implementieren des Verfahrens
nach einem der Ansprüche 2 bis 4 umfasst.
13. Vorrichtung, die Folgendes umfasst:
ein Mittel zum Empfangen (602), an einem drahtlosen Standby-Controller (118) und von
einem aktiven drahtlosen Controller (110), einer MAC-Adresse einer Schicht-2-Schaltung
(302);
ein Mittel zum Übertragen (604), nachdem die Schicht-2-Schaltung (302) einen Schnell-Umschalt-Tunnel
zwischen der Schicht-2-Schaltung (302) und dem drahtlosen Standby-Controller (118)
aufgebaut hat, einer Nachricht (324) an die Schicht-2-Schaltung (302), um den Schnell-Umschalt-Tunnel
zu aktivieren; und
ein Mittel zum Empfangen (606) von Daten, die ursprünglich für den aktiven drahtlosen
Controller (110) bestimmt waren, an dem drahtlosen Standby-Controller (118) über den
Schnell-Umschalt-Tunnel.
14. Vorrichtung nach Anspruch 13, das ferner ein Mittel zum Implementieren des Verfahrens
nach einem der Ansprüche 6 bis 10 umfasst.
15. Computerprogramm, Computerprogrammprodukt oder computerlesbares Medium mit Anweisungen,
die, wenn sie von einem Computer ausgeführt werden, den Computer veranlassen, die
Schritte des Verfahrens nach einem der Ansprüche 1 bis 4 oder einem der Ansprüche
5 bis 10 auszuführen.
1. Procédé de transition d'un contrôleur sans fil actif à un contrôleur sans fil de secours,
comprenant :
la réception (502), au niveau d'un commutateur de couche 2 (302), d'un premier message
pour établir un tunnel de recommutation rapide pour passer d'un premier contrôleur
sans fil (110) à un second contrôleur sans fil (118), dans lequel le tunnel de recommutation
rapide se trouve entre le commutateur de couche 2 (302) et le second contrôleur sans
fil (118), dans lequel le premier contrôleur sans fil (110) est un contrôleur sans
fil actif, et le second contrôleur sans fil (118) est un contrôleur sans fil de secours
;
en réponse à la réception du premier message, l'établissement, par le commutateur
de couche 2 (302), du tunnel de recommutation rapide comme chemin de secours ou de
sauvegarde vers le second contrôleur sans fil (118) pour des données destinées au
premier contrôleur sans fil (110). ;
la réception (504), au niveau du commutateur de couche 2 (302), d'un deuxième message
(324) pour déclencher l'utilisation du tunnel de recommutation rapide ;
en réponse à la réception du deuxième message, l'activation du tunnel de recommutation
rapide ;
la réception (506) de données au niveau du commutateur de couche 2 (302) destinées
au premier contrôleur sans fil (110) ; et
le transfert (508) des données au second contrôleur sans fil (118) par l'intermédiaire
du tunnel de recommutation rapide au lieu du premier contrôleur sans fil (110) pour
passer du contrôleur sans fil actif au contrôleur sans fil de secours.
2. Procédé selon la revendication 1, dans lequel le commutateur de couche 2 (302) reçoit
le premier message à partir du premier contrôleur sans fil (110).
3. Procédé selon l'une quelconque des revendications 1 à 2, comprenant en outre :
la réception, au niveau du commutateur de couche 2 (302), d'une adresse MAC du second
contrôleur sans fil (118) .
4. Procédé selon l'une quelconque des revendications 1 à 3, comprenant en outre :
la réception, au niveau du commutateur de couche 2 (302), d'un troisième message ordonnant
au commutateur de couche 2 (302) de supprimer le tunnel de recommutation rapide, dans
lequel, facultativement, la réception du troisième message intervient après l'achèvement
d'un processus de transmission de protocole de résolution d'adresse gratuit associé
au second contrôleur sans fil (118) .
5. Procédé comprenant :
la réception (602), au niveau d'un contrôleur sans fil de secours (118) et à partir
d'un contrôleur sans fil actif (110), d'une adresse MAC d'un commutateur de couche
2 (302) ;
la transmission (604), après que le commutateur de couche 2 (302) a établi un tunnel
de recommutation rapide entre le commutateur de couche 2 (302) et le contrôleur sans
fil de secours (118), d'un message (324) au commutateur de couche 2 (302) pour activer
le tunnel de recommutation rapide ; et
la réception (606) de données initialement destinées au contrôleur sans fil actif
(110) au niveau du contrôleur sans fil de secours (118) par l'intermédiaire du tunnel
de recommutation rapide.
6. Procédé selon la revendication 5, comprenant en outre :
la transmission d'un avis de protocole de résolution d'adresse gratuit à des clients
du contrôleur sans fil de secours (118), dans lequel, facultativement, après l'achèvement
d'un processus de remplissage d'une table MAC avec des entrées pour les clients sur
la base de la transmission de l'avis de protocole de résolution d'adresse gratuit,
la transmission d'un deuxième message au commutateur de couche 2 (302) pour supprimer
le tunnel de recommutation rapide, comprenant facultativement en outre :
la réception de données supplémentaires au niveau du contrôleur sans fil de secours
(118) après la suppression du tunnel de commutation rapide.
7. Procédé selon la revendication 5 ou 6, dans lequel la transmission du message (324)
au commutateur de couche 2 (302) pour activer le tunnel de recommutation rapide a
lieu après que le contrôleur sans fil actif (110) cesse de fonctionner.
8. Procédé selon l'une quelconque des revendications 5 à 7, comprenant en outre :
la commutation du flux de données depuis le contrôleur sans fil actif (110) vers le
contrôleur sans fil de secours (118) .
9. Procédé selon l'une quelconque des revendications 5 à 8, dans lequel les données sont
reçues à partir d'une passerelle (114) vers le commutateur de couche 2 (302).
10. Procédé selon l'une quelconque des revendications 5 à 9, comprenant en outre :
la réception de données supplémentaires au niveau du contrôleur sans fil de secours
(118) une fois que des entrées MAC pour des clients (102, 104) de points d'accès (106)
associés au contrôleur sans fil de secours (118) sont terminées et que le tunnel de
recommutation rapide a été supprimé.
11. Appareil comprenant :
des moyens pour recevoir (502), au niveau d'un commutateur de couche 2 (302), un premier
message pour établir un tunnel de recommutation rapide pour passer d'un premier contrôleur
sans fil (110) à un second contrôleur sans fil (118), dans lequel le tunnel de recommutation
rapide se trouve entre le commutateur de couche 2 (302) et le second contrôleur sans
fil (118), dans lequel le premier contrôleur sans fil (110) est un contrôleur sans
fil actif, et le second contrôleur sans fil (118) est un contrôleur sans fil de secours
;
des moyens pour établir, par le commutateur de couche 2 (302), en réponse à la réception
du premier message, le tunnel de recommutation rapide comme chemin de secours ou de
sauvegarde vers le second contrôleur sans fil (118) pour des données destinées au
premier contrôleur sans fil (110) ;
des moyens pour recevoir (504), au niveau du commutateur de couche 2 (302), un deuxième
message (324) pour déclencher l'utilisation du tunnel de recommutation rapide ;
des moyens pour activer, en réponse à la réception du deuxième message, le tunnel
de recommutation rapide ;
des moyens pour recevoir (506) des données au niveau du commutateur de couche 2 (302)
destinées au premier contrôleur sans fil (11 0) ; et
des moyens pour transférer (508) les données au second contrôleur sans fil (118) par
l'intermédiaire du tunnel de recommutation rapide au lieu du premier contrôleur sans
fil (110) pour passer du contrôleur sans fil actif au contrôleur sans fil de secours.
12. Appareil selon la revendication 11, comprenant en outre des moyens pour mettre en
œuvre le procédé selon l'une quelconque des revendications 2 à 4.
13. Appareil comprenant :
des moyens pour recevoir (602), au niveau d'un contrôleur sans fil de secours (118)
et à partir d'un contrôleur sans fil actif (110), une adresse MAC d'un commutateur
de couche 2 (302) ;
des moyens pour transmettre (604), après que le commutateur de couche 2 (302) a établi
un tunnel de recommutation rapide entre le commutateur de couche 2 (302) et le contrôleur
sans fil de secours (118), un message (324) au commutateur de couche 2 (302) pour
activer le tunnel de recommutation rapide ; et
des moyens pour recevoir (606) des données initialement destinées au contrôleur sans
fil actif (110) au niveau du contrôleur sans fil de secours (118) par l'intermédiaire
du tunnel de recommutation rapide.
14. Appareil selon la revendication 13, comprenant en outre des moyens pour mettre en
œuvre le procédé selon l'une quelconque des revendications 6 à 10.
15. Programme informatique, produit programme informatique ou support lisible par ordinateur
comprenant des instructions qui, lorsqu'elles sont exécutées par un ordinateur, amènent
l'ordinateur à exécuter les étapes du procédé selon l'une quelconque des revendications
1 à 4 ou l'une quelconque des revendications 5 à 10.